PROJECT ABSTRACT No treatments are available to prevent Alzheimer?s disease, which currently affects 5.8 million Americans. Alzheimer?s risk can be reduced through healthy diets, stress reduction and physical activity, yet maintaining these can be difficult in practice due to cost and low motivation. Addressing these barriers, urban planning and public health researchers have evidenced neighborhood characteristics that promote health by offering amenities encouraging health behaviors such as walking. Greenspace (public and private areas with vegetation) is one such neighborhood feature previously associated with reduced Alzheimer?s risk and slower cognitive decline in the few published studies to date. Dr. Besser?s short-term research goal is to advance the research on this topic, to assess if neighborhood greenspace is associated with brain aging in older adults. The K01 specific aims are to determine if living in neighborhoods with greater vegetation and better access to parks in early, mid, and late-life is associated with slower rates of cognitive decline and less brain atrophy in cognitively normal older adults, and whether these associations vary by sex, race, apolipoprotein E genotype (genetic risk factor for Alzheimer?s disease), and geographic region. This longitudinal, observational study will combine clinical and brain volume data from three Alzheimer?s Disease Centers, a mailed questionnaire, and neighborhood greenspace measures derived using geographic information systems. Outcome variables will include cognitive domain (episodic memory, language, attention, executive function) and brain volume measures (hippocampal volume, white matter hyperintensities). Multi-level linear mixed models will account for neighborhood clustering and control for confounders (e.g., demographics, neighborhood socioeconomic status). The parallel career development plan involves: 1) learning to develop key neighborhood built environment and brain aging measures; 2) advancing and developing specialized primary data collection skills; 3) gaining knowledge in the biology and epidemiology of aging and cognitive neuroscience; 4) preparing and submitting the first R01 proposal; and 5) cultivating multidisciplinary collaborations. Dr. Besser?s institution, Florida Atlantic University, offers a highly supportive environment with all of the necessary faculty, teaching, financial, and research supports and rich opportunities for multidisciplinary and collaborative research. The primary mentor and co-mentor are experts in their respective fields of neurology/aging research and urban and regional planning. Dr. Besser?s institutional environment, career development plan, and specific aims are ideally suited to enable her long-term goal to become an expert and independent research scientist with an established, innovative, R01-funded research program focused on neighborhood built environments to support healthy brain aging.